scholarly journals Mechanical contribution of silica fume and hydrated lime addition in mortars assessed by ultrasonic pulse velocity tests

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Nacim Khelil ◽  
◽  
Amar Kahil ◽  
Said Boukais ◽  
◽  
...  
Keyword(s):  
Silica Fume ◽  
Ultrasonic Pulse Velocity ◽  
Hydrated Lime ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Lime Addition

scholarly journals Evaluating the Durability of Green Cement Mortar Using Ultrasonic Pulse Velocity

2021 ◽  
Vol 877 (1) ◽  
pp. 012049
Author(s):  
Ali Abdulridha ◽  
Saif S. AlQuzweeni ◽  
Rasha S. AlKizwini ◽  
Zahra A. Saleh ◽  
K. S. Hashem
Keyword(s):  
Silica Fume ◽  
Cement Mortar ◽  
Experimental Studies ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Cement Kiln Dust ◽  
Cement Kiln ◽  
Negative Consequences ◽  
Kiln Dust

Abstract Various experimental studies have highlighted the negative consequences of Portland cement on health and the environment, such as toxic emissions and alkaline sewage. The development of environmentally acceptable substitutes for cement is thus one of the objectives of current investigations. The proposed environmental alternatives to cement, nevertheless, might have detrimental impacts on the concrete’s characteristics. This investigation intends to study the suitability as alternatives to cement in cement mortar, using industrial wastes like silica fume and cement kiln dust. As a replacement for cement, the cement mortars developed in this research continue from 0% to 60% silica fume and cement kiln dust. Ultrasonic pulse velocity tests at 1 to 4 weeks of age were conducted on hardened specimens. The findings showed that a low reduction in the pulse velocity resulted from high proportions of silica fume and cement kiln dust replacements, whereas an improvement in the characteristics of the mortars with low replacement ratios. Using low kiln dust and silica fume of 20 to 40%, the durability of mortars may increase.

scholarly journals Physical and Chemo/Mechanical behaviors of fly ash and silica fume belite cement pastes- Part I

NanoNEXT ◽  
2021 ◽  
pp. 1-15
Author(s):  
Darweesh H.H.M
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Total Porosity ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Heat Of Hydration ◽  
Hardened Cement ◽  
Cement Pastes ◽  
Belite Cement

Physical, chemical and mechanical properties of high belite cement (HBC) blended with high pulverized fly ash (HPFA) with stable ratio of silica fume (SF) in comparison with Portland cement (OPC) were investigated. Results showed that the water of consistency and setting times (Initial and final) tended to increase with the increase of HPFA content. The bulk density and compressive strength were also improved and enhanced with the increase of HPFS content at all hydration times, but only up to 15 % HPFA, and then decreased with further increase.  However, the total porosity slightly decreased, but started to increase with further increase of >15 % HPFA. The free lime content of the pure OPC and HBC gradually were increased as the hydration times progressed up to 90 days, while those of blended cements increased only up to 7 days and then decreased onward. The results were confirmed by measuring the heat of hydration and ultrasonic pulse velocity for the optimum cement pastes comparing with those of both OPC and HBC. The heat of hydration of the optimum cement pastes was decreased at all hydration times and become lower than those of OPC and HBC. The ultrasonic pulse velocity test (USPV) proved that the uniformity and quality of the matrix of the hardened cement pastes are good with no cracks.

scholarly journals HUBUNGAN CEPAT RAMBAT GELOMBANG ULTRASONIK TERHADAP MUTU BETON TANPA AGREGAT KASAR

2019 ◽  
Vol 2 (1) ◽  
pp. 199
Author(s):  
David Chandra ◽  
Daniel Christianto
Keyword(s):  
Silica Fume ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Destructive Test ◽  
Non Destructive

Dalam penelitian ini mempelajari mengenai hubungan cepat rambat gelombang ultrasonik terhadap mutu beton tanpa agregat kasar. Campuran beton yang dibuat tidak menggunakan agregat kasar, hanya semen OPC, pasir silika, air, silica fume, tepung marmer dan superplasticizer. Tujuan tidak digunakannya agregat kasar adalah untuk meningkatkan homogenitas material penyusun beton dan meningkatkan kepadatan kering beton. Maka dari itu dalam material penyusun terdapat tepung marmer sebagai filler dan superplasticizer untuk meningkatkan kepadatan kering, ada juga silica fume juga sebagai filler dan meningkatkan kepadatan kering. Benda uji yang dibuat adalah beton tanpa agregat kasar berbetntuk silinder dengan diameter 10 cm dan tinggi 20 cm. Nilai cepat rambat didapatkan dengan menggunakan salah satu metode non-destructive test (NDT) yaitu tes Ultrasonic Pulse Velocity (UPV) dengan cara direct/langsung. Nilai kuat tekan didapatkan dengan melakukan uji tekan pada benda uji. Setelah nilai kecepatan dan kuat tekan didapatkan, dibuatlah diagram pencar dan regresinya untuk mendapatkan formula kuat tekan yang baru. Dari penelitian ini dapat disimpulkan bahwa jika nilai cepat rambat semakin tinggi maka nilai mutu beton cenderung tinggi juga, semakin berat massa benda uji maka nilai cepat rambat dan kuat tekan cenderung tinggi juga. Dihasilkan juga formula kuat tekan (f’c) dari hasil regresi yaitu :  dengan satuan standard international.

The Combined Effect of CKD and Silica Fume on the Mechanical and Durability Performance of Cement Mortar

2021 ◽  
Vol 895 ◽  
pp. 59-67
Author(s):  
Mayadah W. Falah ◽  
Alaa Adnan Hafedh ◽  
Safa A. Hussein ◽  
Zainab S. Al-Khafaji ◽  
Ali A. Shubbar ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Cement Kiln ◽  
Substitute Products

To manufacture high-strength and high-performance concrete, the incorporation of silica fume with concrete was becoming popular nowadays. When utilizing various amounts of cement substitute products, the design becomes even more complicated. The latest research has been dedicated to researching the applicability of cement substitute products for cement kiln dust (CKD) and silica fume (SF). In permeability and compressive strength terms, the effect of these components on the efficacy of the concrete would be studied. Also, the materials proposed might limit greenhouse gas emissions, which will mitigate climate change on other causes of global pollution. Casting a standard concrete cube (100 percent OPC) equivalent to (150 gm) would initiate the experiment, which was utilized later for comparative purposes. The industrial waste materials (SF and CKD) was be applied as cement substitution proportions (10 percent, 20 percent, and 30 percent) of the dry cement weight at varying percentages of each component (5 percent, 10 percent, and 15 percent). Eventually, after 7, 14, 28 days, the compressive strength shift would be calculated. The permeability of the latest concrete will be checked after (7, 14, and 28) days of healing utilizing ultrasonic pulse velocity (UPV) technology. The experimental findings indicate that with a specimen comprising 20 percent of (SF and CKD) relative to (100 percent OPC) specimen, there is an improvement in compressive intensity and pulse velocity values in various curing times and specimens of various (SF and CKD) specimen M3 have a decrease in pulse velocity value after 7 curing days.

Compressive Strength and Ultrasonic Pulse Velocity of Mortars and Pastes, Elaborated with Slaked Lime and High Purity Hydrated Lime, for Restoration Works in México

2020 ◽  
Vol 862 ◽  
pp. 51-55
Author(s):  
Elena Guadalupe Navarro-Mendoza ◽  
Elia Mercedes Alonso-Guzmán ◽  
Jose Luis Ruvalcaba-Sil ◽  
Adrià Sánchez-Calvillo ◽  
Wilfrido Martínez-Molina ◽  
...  
Keyword(s):  
Compressive Strength ◽  
High Purity ◽  
Ultrasonic Pulse Velocity ◽  
Hydrated Lime ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Powder Surface ◽  
Slake Lime ◽  
Knowing That ◽  
Slaked Lime

Restoration works for the cultural heritage in México have commonly used traditional materials, being the slake lime one of the main solutions employed. Nevertheless, other lime products have not been studied or applied in patrimonial works. The main objective of this research was to verify if high purity limes can be used as an alternative for restoration works, knowing that they have a higher powder surface area and consequently great efficiency. Compressive strength and ultrasonic pulse velocity tests, (UPV), were carried on specimens of slaked lime and high purity limes in pastes and mortars, to compare the values obtained and decide in which restoration works they could be employed. Results showed a better performance of the high purity lime in mortars and slightly better values of the slaked lime for pastes.

Effect of Treated Sago Pith Waste Ash and Silica Fume to the Mechanical Properties of Fly Ash-Based Geopolymer Brick

2021 ◽  
Vol 879 ◽  
pp. 100-114
Author(s):  
Izwan B. Johari ◽  
Md Azlin Md Said ◽  
Mohd Amirul B. Mohd Snin ◽  
Nur Farah Aqilah Bt. Ayob ◽  
Nur Syafiqah Bt. Jamaluddin ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Silica Fume ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Partial Replacement ◽  
Rebound Hammer ◽  
Compressive Strength Test ◽  
Sago Pith Waste

This paper investigates the effect of partial replacement of fly ash with sago pith waste ash and silica fume in fabricating the geopolymer mortar concrete. The mixtures of geopolymer mortar concrete were prepared by replacing sago pith waste ash and silica fume at 5% of total weight of fly ash. There were six specimens of geopolymer mortar cubes and bricks fabricated in this study. The specimens are tested with compressive strength test, rebound hammer test and ultrasonic pulse velocity test. The results from the tests are compared with some existing published works as to clarify the effect of replacing the fly ash with sago waste and silica fume on the strength of concrete. Comparisons had been made and concluded that the molarity of alkaline solution, Al3O2 and CaO influenced the development of compressive strength along the curing time of fly ash based geopolymer concrete.

scholarly journals Ultrasonic Pulse Velocity and Morphology of High Strength Concrete with PVC Waste Aggregate

2020 ◽  
Vol 8 (5) ◽  
pp. 3783-3788 ◽  
Keyword(s):  
Silica Fume ◽  
High Strength Concrete ◽  
High Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
High Ratio ◽  
Hardened Cement ◽  
Strength Concrete ◽  
Residual Properties

In this paper, morphology and ultrasonic pulse velocity (UPV) of high strength concrete with a relatively high ratio of condensed silica fume and PVC waste aggregate as sand replacement have been examined. The plastic aggregate was obtained from shredding PVC waste sheets used for secondary roofing and covering walls. Variables tested were PVC plastic grading and ratio of sand replacement with such plastic, in addition to curing time of concrete. Results of scanning electron microscopy showed that there is a good bond between PVC aggregate particles and hardened cement paste. There was a relatively small reduction of UPV value of concrete, increased with increasing PVC aggregate content, reached 14.3% at 40% PVC content. The UPV lost is slightly increased with increasing concrete age from 7 days to 56 days. Results also showed that the effect of PVC aggregate grading on the residual UPV is not important. Based on the measured residual properties of high strength with silica fume and PVC granules, there is a high degree of silica fume hydration and the existence of PVC particles has no effect on such hydration.

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